Wednesday, May 18, 2022

How mitochondria distribute their transcriptome throughout the cell?

Inside mitochondria and their fascinating genome.

Mitochondria are known as the cells’ powerhouse- it produces energy for cells to function as multicellular organisms. Mitochondria holds the genetic information for making energy.

EPFL scientists have observed – for the first time in living cells – the way mitochondria distribute their transcriptome throughout the cell. 

EPFL biophysicist Suliana Manley and her team collaborated with Jean-Claude Martinou’s cell biology group from the University of Geneva to look deep within living cells.

RNA granules in mitochondria are smaller than the diffraction limit of light. Scientists used super-resolution microscopy to observe these mitochondrial RNAs. They found that mitochondrial RNAs are packaged into tiny liquid droplets that can fuse and break apart.

Manley said“The organization of genetic information contained within mitochondria is highly dynamic thanks to this liquid-like aspect of its RNA granules. The way they continuously exchange material gives us insight into how mitochondria can make sure they have the genetic information they require to produce energy within cells.”

The mitochondrial genome is independent of the cell’s genome, so the mitochondria’s genetic identity is separate from the cell’s genetic identity and the rest of the organism. Mitochondria’s genome is only around 16 thousand base pairs long, whereas the DNA of the human cell, more than 100,000 times as long, consists of 3 billion base pairs.

Understanding how mitochondria work is essential to understand cell functions/malfunctions better. Especially in cells that require large amounts of energy like nerve and muscle cells, dysfunctional mitochondria can have devastating consequences, resulting in severe disease.

Journal Reference:
  1. Rey, T., Zaganelli, S., Cuillery, E. et al. Mitochondrial RNA granules are fluid condensates positioned by membrane dynamics. Nat Cell Biol (2020). DOI: 10.1038/s41556-020-00584-8


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